In recent years, as VoIP (Voice over Internet Protocol) and other technologies appear, communication systems, such as IP telephony using IP networks are coming into widespread use. In order to maintain communication quality in the IP networks using the VoIP and the like, it is important to grasp communication status in advance and accurately when network load increases.
Patent Literature 1 given below discloses a method for measuring packet delay times and jitter (fluctuation) characteristics by employing a real network in operation. This method measures transfer delay times by inserting time stamp information into measurement packets at the time of transmission and transferring the measurement packets in a measurement section of the network.
However, in the prior art method, when the measurement is performed by using inexpensive devices such as PC (personal computers) and the like, delays occurs due to the influence of a CPU (central processing unit) and an OS (operating system) in a receiving terminal and this delay in the receiving terminal cannot be distinguished from the delay in the network. Thus, there is a problem in that the delay in the network that is desired to be measured in the first place cannot be measured accurately.
Patent Literature 1: Japanese Unexamined Patent Publication No. 2001-333092